Electric strike mechanism

ABSTRACT

A door locking mechanism employing an internally mounted solenoid for providing both fail secure and fail safe operations employing a pivotally mounted keeper for selectively opening and closing a strike block with keeper being controlled by a locking yoke which is selectively movable by the solenoid.

This application is a continuation in part of U.S. patent applicationSer. No. 08/072,109 filed Jun. 7, 1993 now abandoned and entitledELECTRIC STRIKE MECHANISM.

This invention relates to door locking mechanisms and more particularlyto a modular design for a door locking mechanism which employs aninternally mounted solenoid for both fail secure and fail safeoperations. The disclosed modular design enables the user to determinethe function, either fail secure or fail safe at the time ofinstallation of the lock mechanism by the positioning of the solenoidwithin the strike.

DESCRIPTION OF THE PRIOR ART

Door locking mechanisms are well known in the prior art but none areknown of a modular design which is compact, easy to install and utilizesa solenoid that provides both fail secure and fail safe operations.

U.S. Pat. No. 4,017,107 discloses an electric door strike employing apivoting shutter moveable between an open position to admit a dead boltwhen the latter is in its extended position and a closed positionwherein a notch for receiving the dead bolt is partially covered. In theclosed position the dead bolt may not be withdrawn from a strike frameexcept by being withdrawn into the door lock mechanism. A shutter ismounted on the shaft of a rotary solenoid which, when energized, pivotsthe shutter and engages a mating detent in the strike frame when theshutter is closed to prevent the shutter from being forced open from aposition externally of the door. A latch spring is mounted within thestrike frame in an interfering position with both the dead bolt and theshutter, the spring being urged by contact with the dead bolt out of thepath of the shutter to permit the latter to pivot into its closedposition.

U.S. Pat. No. 4,026,589 discloses a door locking mechanism that employsa dead bolt and spring latch released by the action of a single keeper.The keeper has two stable limit positions, i.e., open or closed. Oncereleased, (by engaging the solenoid) the keeper is held in its openposition allowing the door to be opened and closed with the dead bolt inits extended position. The dead bolt moving toward the door closedposition engages an abutment member which urges the keeper toward theclosed and locked position.

U.S. Pat. No. 4,595,220 discloses a dead bolt sensing and strike closingmechanism employing a rotatable keeper moveable between open and closedpositions. An abutment member is connected to a rotatable keeper and isselectively rotatable with the rotatable keeper. A sensing arm isconnected to the strike case for sensing the presence of the dead boltin the strike case. The sensing arm selectively disengages the abutmentmember for allowing the abutment member to rotate with the rotatablekeeper if the dead bolt is detected within the strike case.

U.S. Pat. No. 4,626,010 discloses a concealed door release mechanismincluding a strike block adapted to receive a latch bolt. A rampedsurface is provided within the strike block for urging the latch boltinto the door to thereby open the door. Structure is provided in thestrike block for preventing the latch bolt from moving into contact withthe ramped surface for maintaining the door closed.

SUMMARY OF THE INVENTION

In accordance with the invention claimed, a new and improved lockingmechanism is provided which provides both fail secure and fail safeoperations with the use of a single solenoid.

It is, therefore, one object of this invention to provide a new andimproved electrically energized locking mechanism.

Another object of this invention is to provide a modular electric strikeemploying an internally mounted solenoid which provides both fail secureand fail safe functions.

A further object of this invention is to provide an electric strikemechanism providing fail secure and fail safe functions with a minimumof moving parts.

A still further object of this invention is to provide such a strikemechanism which may be inexpensively constructed in a compact modularform.

A still further object of this invention is to provide an improvedelectrical strike mechanism which may be converted from fail secure tofail safe, or fail safe to fail secure without additional components.

A still further object of this invention is to provide an improvedelectrical strike mechanism which employs a locking yoke that providesdouble lock security to the strike by preventing unauthorized rotationof the locking yoke except upon activation of a solenoid.

Yet another object of this invention is to provide an electrical strikemechanism which employs a certain synchronizing function using a Genevamechanism to maintain a proper relationship between the locking yoke andthe keeper of the lock mechanism.

Further objects and advantages of the invention will become apparent asthe following description proceeds and the features of novelty whichcharacterize the invention will be pointed out with particularity in theclaims annexed to and forming a part of this specification.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention may be more readily described by reference to theaccompanying drawings in which:

FIG. 1 is a perspective view of an electric strike installed in a doorjamb and constructed in accordance with the teachings of the presentinvention;

FIG. 2 is an exploded perspective view of the components of the electricstrike shown in FIG. 1;

FIG. 3 is a perspective view of the operating module portion of theelectric strike;

FIG. 4 is a right end view of FIG. 3;

FIG. 5 is a cross sectional view of FIG. 4 showing the connector linkand cam so positioned as to place the locking yoke in the unlockedposition;

FIG. 6 is a cross sectional view of FIG. 4 showing the locking yokemoved by the solenoid to its unlocked position;

FIG. 7 is the same view as FIG. 5 but showing the connector link and camso positioned as to place the locking yoke in the locked position;

FIG. 8 is the same view as FIG. 6 but showing the locking yoke moved tothe locked position;

FIG. 9 is a view of the keeper of FIGS. 1 and 2 shown in the open orunlocked position; and

FIG. 10 is a cross section of the keeper of FIG. 9 taken along the line10--10 showing the keeper return spring.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring more particularly to the drawings by characters of reference,FIGS. 1-10 disclose an improved electric strike 10 mounted in a doorjamb 11 and comprising three basic assemblies, namely an enclosure 12,and operating module 13 and a solenoid assembly 14.

The strike enclosure comprises a case 15, cover 16 and face plate 17 inaddition to mounting hardware, bolts 18 and nuts 19. The case which maybe constructed of a formed and welded stainless steel sheet is providedfor mounting and protecting the operating components of the electricstrike mechanism. Cover 16, which may be an aluminum casting is used forsealing the enclosure to protect the components and for providing easyaccess for service purposes. The face plate is stamped from a stainlesssteel sheet to provide a decorative trim.

The operation module 13, as shown in FIGS. 2, 3 and 4, comprises ahousing 20, keeper 21, keeper return spring 26 (shown in FIG. 10),locking yoke 23, pivot pins 22 and 22' and yoke actuator 25. Alsoincluded in the operating module 13 are solenoid link 24, connector link39, cam 38 and associated assembly hardware. The keeper 21 is secured toenclosure 20 at four points thus distributing any forces generated bypushing on the door in the opening direction.

Solenoid assembly 14, as shown in FIGS. 2 and 3, is mounted in theoperating module 13 and held therein by bolt 33 which threadedly fitsinto the operating module enclosure 20. The solenoid assembly 14comprises body 34, plunger 35, solenoid return spring 28 and clevises 36and 36'. Plunger 35 of solenoid assembly 14 is biased to its deenergizedposition shown in FIG. 4 by conical coiled spring 28 surrounding theplunger. When the spring is compressed it flattens to a height of onecoil. Clevis 36' is secured by pin 37 to solenoid link 24 when failsecure (locked with power off) operation is desired. When fail safe(locked with power on) operation is desired, the solenoid is rotated endfor end in enclosure 20 and clevis 36 is connected to solenoid link 24by pin 37.

Whether the electric strike is operating in a fail safe, or fail securemode, the operating module 13 performs the same function, that oflocking or unlocking keeper 21. FIG. 1 shows keeper 21 in its closedposition with the keeper return spring tending to maintain the keeper inthat position.

As shown in FIG. 8, the operating module 13 contained in enclosure 12secures a latch bolt 30 and a sliding element 31 in its depressedposition carried by a door 32 when door 32 is in the closed position.Latch bolt 30 and sliding element 31 are retracted within door 32 asdoor 32 is opened by door knob (not shown).

General Operation

The clevis 36 containing a pin 37 extending between its legs on the topof plunger 35 is connected to solenoid link 24 in the manner shown inFIG. 4. Solenoid link 24 engages pin 37 and connector link 39 extendinglaterally out of the other end of solenoid link 24 to pivot the cam 38.Locking yoke 23 comprises a U-shaped frame having its legs extending onealong the base inside housing 20 and the other along the top and insideof housing 20, as shown in FIGS. 2 and 3.

Locking yoke 23 is pivotally mounted in housing 20 at approximately thecenter point of each of its legs by locking yoke pivot pins 22 and 22'to move in a predetermined arcuate manner under the effects of lockingyoke actuator 25. Locking yoke actuator 25 is 24, actuated by solenoid14 through solenoid link connecting link 39 and cam 38 and is guided byguides 49 as shown in FIGS. 4, 5 and 7. With cam 38 rotated to its fullcounterclockwise position (FIG. 7), locking yoke actuator 25 secureslocking yoke 23 in the locked position. This prevents possible pickingof the electric strike by moving locking yoke 23 with a tool fromoutside the electric strike. Movement of locking yoke 23 by locking yokeactuator 25 in the manner shown in FIG. 6 causes locking yoke 23 todisengage from lock pins 40 mounted within grooves in the sides ofkeeper 21. This movement is caused by the full clockwise rotation of cam38 (FIG. 5). Cam 38 is moved to its full counterclockwise position bythe full extension (out of the operating module 13) of connector link 39and the full counterclockwise rotation of solenoid link 24 about itspivot pin 41 (FIG. 4).

Cam 38 rotates on pivot pin 48 and drives locking yoke actuator 25through drive pin 46 as pin 46 moves across actuator 25 through driveslot 45. Also, locking yoke activator 25 moves on pivot pin 48 throughclearance slot 47. Slots 45 and 47 are contained in locking yokeactuator 25. Cam pivot pin 48 is mounted in housing 20 while cam linkagepin 46 travels through a clearance slot 50 in housing 20.

The disengagement of locking yoke 23 from engagement pins 40 releaseskeeper 21 and permits the movement of door 32 and its latch bolt 30 tomove from door locked position to door open position as shown in FIG. 6.As the door opens, latch bolt 30 contacts keeper 21 rotating it towardthe door open position. When latch bolt 30 clears keeper 21, the keeperreturn spring 26, FIGS. 9 and 10, moves the keeper toward its closedposition. Interaction of the Geneva mechanism components 43 and 42 onkeeper 21 and locking yoke 23, respectively, ensure that locking yoke 23cannot return to its locked position until keeper 21 has fully closed.Additionally, with the Geneva mechanism or movement positioned as shownin FIG. 8, separate locking means is provided by the Geneva mechanism.As used herein, the Geneva mechanism comprises a stop formed by twointerfering cams 42 and 43 formed one on each leg of locking yoke 23,Cam 42 inhibits rotation of keeper 21 depending on the rotationalposition of the mating parts.

Fail Secure Operation

In the fail secure mode, solenoid 14 is oriented in operating module 13so that with power off connector link 39 is extended out of theoperating module 13 thereby locking the electric strike (FIGS. 7 and 8).Application of power to solenoid 14 serves to push connector link 39into the operating module 13 thus unlocking the electric strike (FIGS. 5and 6).

Fail Safe Operation

To operate in the fail safe mode, solenoid 14 is reversed, end to end,in the operating module 13. With this orientation, if power is offconnector link 39 is retracted into the operating module 13 (by means ofconical spring 28) and the electric strike is unlocked (FIGS. 5 and 6).With the application of power, connector link 39 is extended from module13 thus locking the electric strike (FIGS. 7 and 8).

Although but two embodiments of the invention have been illustrated anddescribed, it will be apparent to those skilled in the art that variouschanges and modifications may be made therein without departing from thespirit of the invention or from the scope of the appended claims.

What is claimed is:
 1. A door locking mechanism comprising:a strikeblock adapted to receive a latch bolt, a pivotal keeper comprising pinmeans for selectively opening and closing said strike block, a firstspring means acting on said keeper for biasing said keeper to a lockedposition, solenoid means positioned in said block and having a plungerextending therefrom and a second spring means mounted around saidplunger for biasing said plunger outwardly of said solenoid means, pivotmeans mounted in said block for arcuate reciprocal movement from a firstposition to a second position under the action of said plunger of saidsolenoid means and from said second position to said first positionunder the action of said second spring means, said pivot means having aslot for engagement with said pin means on said keeper when saidsolenoid means is deenergized, an actuator means pivotally mounted onsaid block for engagement with said plunger of said solenoid means atone end thereof and with said pivot means at the other end, saidsolenoid means when electrically energized rotating said actuator meansto cause it to engage and arcuately move said pivot means, said pivotmeans upon arcuate movement to said second position removing its slotfrom around said pin means to release said keeper rendering it movableby a door latch to its open position and sequentially under the actionof said first spring means moving it back to its locked position.
 2. Thedoor latching mechanism set forth in claim 1 wherein:said pivot meanscomprises a locking yoke, said locking yoke comprises a pair of spacedslots, and said pin means comprises a pair of spaced pins one forengaging with each of said slots in said locking yoke.
 3. The doorlatching mechanism set forth in claim 1 in further combination with:alocking means comprising interfering cams one mounted on said keeper andone mounted on said locking yoke which prohibit said locking yoke fromreturning to its locked position until said keeper returns to its closedposition and is ready to be locked.
 4. A door locking mechanismcomprising:a strike block adapted to receive a latch bolt, a pivotalkeeper for selectively opening and closing said strike block andcomprising pin means, a keeper return spring acting on said keeper forbiasing said keeper to a locked position, solenoid means positioned insaid block so that when energized the keeper is free to move to an openand unlocked position and having a plunger extending therefrom and aplunger return spring mounted around said plunger for biasing saidplunger outwardly of said solenoid means thus allowing said keeper tomove to a closed and locked position when the solenoid means isdeenergized, a locking yoke mounted in said block for arcuate reciprocalmovement from a first position with the solenoid means deenergized to asecond solenoid position with the solenoid means energized, said lockingyoke having a slot for engagement with said pin means on said keeper tolock said keeper in a given position, an actuator means reciprocallymounted on said block for engagement with said plunger of said solenoidmeans at one end thereof and with said locking yoke at the other end,said solenoid means when electrically energized sliding said actuatormeans to cause it to arcuately move said locking yoke to the unlockedposition, said locking yoke upon arcuate movement to said secondsolenoid position removing its slot from around said pin means torelease said keeper rendering it movable by a door latch to its open andunlocked position and sequentially under the action of said deenergizedsolenoid means moving it back to its closed and locked position.
 5. Thedoor locking mechanism set forth in claim 4 in further combinationwith:a locking means comprising interfacing cams one mounted on saidkeeper and one mounted on said locking yoke which prohibit said lockingyoke from returning to its locked position until said keeper returns toits closed position and is ready to be locked.
 6. A door lockingmechanism comprising:a strike block adapted to receive a latch bolt , apivotal keeper for selectively opening and closing said strike block andcomprising pin means, a keeper return spring acting on said keeper forbiasing said keeper to a closed and locked position, solenoid meanspositioned in said block so that when energized said keeper is in aclosed and locked position and having a plunger extending therefrom anda plunger return spring mounted around said plunger for biasing saidplunger outwardly of said solenoid means thus allowing said keeper tomove to an open and unlocked position when the solenoid is deenergized,a locking yoke mounted in said block for arcuate reciprocal movementfrom a first position with said solenoid means energized to a secondsolenoid deenergized position under the action of said solenoid means,said locking yoke having a slot for engagement with said pin means onsaid keeper to lock said keeper in said first position, and an actuatormeans reciprocally mounted on said block for engagement with saidplunger of said solenoid means at one end thereof and with said lockingyoke at the other end, said solenoid means when electrically energizedsliding said actuator means to cause it to arcuately move said lockingyoke to the locked position, said locking yoke upon arcuate movement tosaid second deenergized position removing its slot from around said pinmeans to release said keeper rendering it movable by a door latch to anopen and unlocked position and sequentially under the action of anenergized solenoid means moving it back to a closed and locked position.7. The door locking mechanism set forth in claim 6 in furthercombination with:a locking means comprising interfering cams one mountedon said keeper and one mounted on said locking yoke which prohibit saidlocking yoke from returning to its locked position until said keeperreturns to its closed position and is ready to be locked.
 8. A doorlocking mechanism comprising:a strike block adapted to receive a latchbolt, a pivotal keeper for selectively opening and closing said strikeblock and comprising pin means, a keeper return spring acting on saidkeeper for biasing said keeper to a closed and locked position, solenoidmeans positioned in said block and having a plunger extending therefromand a plunger return spring mounted around said plunger for biasing saidplunger outwardly of said solenoid means, a U-shaped locking yokemounted in said block for arcuate reciprocal movement from a firstposition to a second position under the action of said solenoid means,said locking yoke having a pair of slots one in each leg of the U-shapedlocking yoke for engagement with said pin means on said keeper to locksaid keeper, and an actuator means reciprocally mounted on said blockfor engagement with said plunger of said solenoid means at one endthereof and with said locking yoke at the other end, said solenoid meanswhen electrically energized sliding said actuator to cause it toarcuately move said locking yoke, said locking yoke upon arcuatemovement to said second deenergized position removing its slot fromaround said pin means to release said keeper rendering it movable by adoor latch to an open and unlocked position and sequentially under theaction of said solenoid means moving it back to a closed and lockedposition.
 9. The door locking mechanism set forth in claim 8 in furthercombination with:a locking means comprising interfering cams one mountedon said keeper and one mounted on said locking yoke which prohibit saidlocking yoke from returning to a locked position until said keeperreturns to a closed position.